If we know the output and input temperatures of the heat exchanging fluids, then which one of the following calculation is not required to determine the number of bends in tube for the equipment?
a) Total heat transfer area required
b) Pipe length
c) Overall heat transfer coefficients
d) Pressure drop in the equipment
Q.2.
Which one of these is not true when the steady state is reached by the heat exchanging fluids in a double pipe HE?
a) Rate of heat transfer becomes constant
b) When their temperatures become stable
c) Wall temperature becomes constant
d) When the two liquids have same temperature
Q.3.
If the Heat Transfer area for a Shell and tube heat exchanger is 15100mmand the radius of the tubes is 30mm, then what is the number of hairpins required if its single pass length is 4cm?
a) 8
b) 2
c) 6
d) 5
Q.4.
If UD = Overall Dirt Heat Transfer coefficient and Uc = Overall Clean Heat Transfer coefficient, then which of the following relation is correct?
a) UD < Uc
b) UD >> Uc
c) UD = Uc
d) UD > Uc
Q.5.
To which side given below should we add fins?
a) Liquid side
b) Gas Side
c) Any side possible
d) Solid side
Q.6.
The Heat Transfer Coefficient remains constant throughout the surface of the fin.
a) False
b) True
Q.7.
By increasing the fin density, the heat transfer coefficient associated with fins__________
a) Increases
b) Decreases
c) Increases tenfold
d) Remains the same
Q.8.
Adding fins inside the tube, that is for the tube side usually ________ the heat transfer coefficient.
a) Decreases
b) Tenfold
c) Does not change
d) Increases
Q.9.
Heat transfer in Agitated Vessels can be carried out by two methods they are ____________
a) Semi coils and Internal coils
b) Jacketed and Plates
c) Plates and Coils
d) Jacketed and Internal coils
Q.10.
The heat transfer coefficient ________ with increasing flow rate.
a) Decreases
b) Remains the same
c) Increases
d) Drops drastically
Q.11.
For very high dp/di, the mixing is very large and the heat transfer coefficient is ______
a) Very low
b) Very high
c) Low
d) High
Q.12.
Which one of the following working model is best suited for fluidized bed combustion boilers?
a) Pneumatic conveying regime
b) Laminar film fluidised bed
c) Moving bed (Dense flow
d) Bubbling fluidized beds
Q.13.
Which one of the heat transfer processes are not involved in a fluidised bed?
a) Heat transfer between different points in the bed
b) Gas-wall heat transfer
c) Heat transfer to the submerged surfaces in contact with the bed
d) Heat transfer between the fluidized bed particles and the larger particles floating in the bed
Q.14.
On complete fluidisation, which one of the following is zero?
a) Heat transfer between different points in the bed
b) Gas-wall heat transfer
c) Heat transfer to the submerged surfaces in contact with the bed
d) Heat transfer between the fluidized bed particles and the larger particles floating in the bed
Q.15.
Heat transfer between the active particle and the fluidized bed is controlled by three mechanisms given below, identify the wrong entry.
a) Particle convection
b) Radiation
c) Particle conduction
d) Gas convection
Q.16.
Which one of the following is not a suitable application of evaporators?
a) Heating
b) Refrigeration
c) Crystallisation
d) Cooling
Q.17.
The following are few demerits of using short tube vertical evaporators, select the incorrect one.
a) Very low heat transfer coefficients with thin fluids
b) Corrosive fluids cannot be used as it increases cleaning cost
c) The fluid stays a long time above the tubes which takes long time to heat up
d) Convoluted tube increase the cost of manufacture
Q.18.
Which one of the following is not an advantage of Long tube evaporators?
a) Good heat transfer coefficients at low temperature gradients
b) Thin fluids have very large product economy
c) Relatively inexpensive to manufacture
d) Low head space required
Q.19.
The following are few demerits of using short tube vertical evaporators, select the incorrect one.
a) Very low heat transfer coefficients with thick fluids
b) Corrosive fluids cannot be used as it increases cleaning cost
c) Long tubes efficiently evaporate and hence recirculation is hardly required
d) Large head room requirement
Q.20.
Which one of the following is not an advantage of forced convection boiling?
a) Very cheap to operate
b) Positive circulation
c) High heat transfer coefficient
d) Low fouling or scaling
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